Comparison of conventional and ultrasound-assisted methods for extraction of nutraceutical compounds from Dendrobium candidum

摘要

The present study was conducted with the objective of developing efficient method of extraction of nutraceutical compounds from protocorms of Dendrobium candidum for the food industry. Conventional heat reflux method was compared with ultrasonic-assisted method for extraction of polysaccharides, polyphenolics and flavonoids. Methanol, ethanol, acetone, acetonitrile and water were used as solvents for heat reflux extraction. Parameters tested for the optimization were methanol concentration (20, 40, 60, 80 and 100%) and duration of treatment (30 min, 1, 2, 4, 6 h). The treatment of samples with 80% methanol for 2-h period proved to be most suitable procedure for extraction of bioactive compounds. Heat reflux method was found superior to ultrasonic-assisted method since it yields higher amounts of bioactive compounds (463.0 mg g ?￠????1 DW polysaccharides, 10.75 mg g ?￠????1 DW polyphenolics and 5.30 mg g ?￠????1 DW flavonoids) and extracts obtained from heat reflux method also showed optimal antioxidant activity.